The effect of power system stabilizers on system performance

The effect of generator controls on a power system´s ability to keep system bus voltages and frequencies constant under the influence of load changes is discussed. This is illustrated by application to the widely used two-area power system model. The effect of load changes on the system´s tie-line buses is shown to change as system controls are added. Power system stabilizers are required to stabilize the system´s inter-area mode, but their addition causes low frequency changes in the load to increase the voltage excursions at the tie buses. For the example case, the voltage excursion is shown to remain within satisfactory limits when power system stabilizers are added